Prevent key view status for specific TopChrome WebUIs

Minor

Commit Hash: 3cc01c9b6a22aee1fee457f29b612c63a7b41dd6

Commit Time: 2026-01-13 00:50:12+00:00

Impact Level: Minor

Generated By: webview2-upstream-sentry

Upstream Review: View Upstream Review 🔗

📋 Summary

This commit addresses an issue where the Reload WebUI's RenderWidget incorrectly becomes the first key view when entering fullscreen on macOS, causing an unwanted focus ring and stealing focus. The fix delegates the decision of canBecomeKeyView to the RenderWidgetHost by adding a new delegate method shouldRefuseBecomingKeyView, allowing specific WebUIs to opt out of key view status. This modification does not prevent items from receiving focus via the Views framework (e.g., tabbing), but strictly prevents macOS from automatically assigning key view status to the RenderWidget container.

Specific changes include:
1. Added a new optional method shouldRefuseBecomingKeyView to the RenderWidgetHostViewMacDelegate protocol
2. Modified the canBecomeKeyView method in render_widget_host_view_cocoa.mm to call this delegate method
3. Implemented this delegate method in the Chrome browser to return YES for specific TopChrome WebUIs (such as Toolbar WebUI)
4. Added the ShouldRefuseBecomingKeyViewForTopChromeWebUI helper function to determine if a specific URL should refuse to become the key view

🎯 Impact Analysis

The impact of this change on WebView2Mac is Minor.

**Impact Analysis:**
1. **Interface Extension**: A new optional method shouldRefuseBecomingKeyView has been added to the RenderWidgetHostViewMacDelegate protocol. Since this is an optional method (marked as @optional), WebView2Mac does not need to implement it immediately and will not encounter compilation errors.

2. **Behavior Change**: The canBecomeKeyView method in render_widget_host_view_cocoa.mm now checks whether the delegate implements the shouldRefuseBecomingKeyView method. If the delegate does not implement this method, the behavior remains unchanged and returns the original value of _canBeKeyView.

3. **WebView2Mac Impact**:
- WebView2Mac uses Remote Cocoa's RenderWidgetHostViewCocoa to manage the NSView for web content
- WebView2Mac integrates with Remote Cocoa through HostingNSWindowBridge and related components
- If WebView2Mac's delegate (the RenderWidgetHostViewMacDelegate implementation) does not implement the new method, behavior remains completely unchanged
- Since this change primarily targets Chrome browser's TopChrome WebUIs (specifically Toolbar WebUI), and WebView2Mac does not use these specific WebUI components, it will not be directly affected

4. **Potential Opportunity**: If WebView2Mac needs to control whether RenderWidgets become key views in certain scenarios (e.g., to prevent automatic focus stealing), it can optionally implement this new delegate method.

**Conclusion**: This change is a backward-compatible interface extension that will not break WebView2Mac's existing functionality. WebView2Mac can continue to operate normally without requiring immediate action.

Impacted Classes:

RenderWidgetHostViewMacDelegate RenderWidgetHostViewCocoa ChromeRenderWidgetHostViewMacDelegate